预应力是锚杆支护中重要的参数,预应力对巷道支护效果有重要影响。分析了锚杆预应力对巷道支护效果的影响,锚杆预紧扭矩与预紧力对应关系。针对目前煤矿井下常用的锚杆施工预紧机具,对比了各种施工机具的优缺点,从技术角度、材料方面以及施工机具方面提出了煤矿井下锚杆预紧力的控制措施,提出了锚杆预紧扭矩的合理范围,并得出对于高强度锚杆及强力锚杆,锚杆的预紧扭矩不是越大越好,而是应该有一个合理的范围。井下试验实测数据表明,对于传统高强度锚杆,预紧扭矩要达到300 N·m,一般不要超过500 N·m;对于强力锚杆,锚杆的预紧扭矩要达到400 N·m,一般不要超过550 N·m,否则锚杆容易扭曲变形甚至屈服。通过井下实例进行了锚杆预紧力控制的试验,锚杆破断现象基本消失,取得了很好的支护效果。

The pre-stress is an important parameter of the bolt support and would have an important influence to the mine roadway support effect.The paper analyz ed the bolt pre-stress affected to the mine roadway support effect and the relevant relationship between the bolt pre-tightening torque and the pre-tension.According to t he conventional pre-tightening tools of the bolting operation in the present underground coal mines, the paper had a comparison on the advantage and disadvantage of each operation tools. From the technology, material and operational tools, the measures to control the bolt pre-tension in underground mine was provided.The rational s cope of the bolt pre-tightening torque was provided . As for the high strength bolt and the powerful bolt, the pre-tightening torque of the bolt would not be the higher the b etter, but shall have a rational scope of the pre-tightening torque. The underground site test measured data showed that as for the traditional high strength bolt, the pre-t ightening torque of the bolt shall be at 300 N.m and generally shall not be over 500 N.m.As for the powerful bolt, the pre-tightening torque of the bolt shall be at 400 N. m and generally shall not be over 550 N.m.Otherwise the bolt would be easy to be deformed and failed.With the underground mine cases, a test of the bolt pre-tension control was conducted and the bolt broken phenomenon was basically eliminated with excellent effect.

“十一五”国家科技支撑计划资助项目(2008BAB36B07)；